...tional Lagrangian here takes the form of a scalar-tensor theory (Sec. 3.3.2). But the non-metric electromagnetic term will, in general, produce violations of EEP. For examples of specific models, see =-=[227, 76]-=-. Another class of non-metric theories are included in the “varying speed of light (VSL)” theories; for a detailed review, see [158] On the other hand, whether one views such effects as a violation of...

... The mass of the dilaton is also much smaller than ms. In realistic applications, this mass must be at least as big as an inverse millimeter (or nearly decouple at long distance for some other reason =-=[33]-=-). Of course this model is not realistic in any case because, because of the dimensionality and the sign of the cosmological constant (among other things). 3. A \noncritical" approach to dS space Sinc...

"... Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made such high precisio ..."

Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made such high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.

Confirming previous heuristic analyses à la Belinskii-Khalatnikov-Lifshitz, it is rigorously proven that certain “subcritical” Einstein-matter systems exhibit a monotone, generalized Kasner behaviour in the vicinity of a spacelike singularity. The D−dimensional coupled Einstein-dilaton-p-form system is subcritical if the dilaton couplings of the p-forms belong to some dimension dependent open neighbourhood of zero [1], while pure gravity is subcritical if D ≥ 11 [13]. Our proof relies, like the recent theorem [15] dealing with the (always subcritical [14]) Einstein-dilaton system, on the use of Fuchsian techniques, which enable one to construct local, analytic solutions to the full set of equations of motion. The solutions constructed are “general” in the sense that they depend on the maximal expected number of free functions.

"... The status of experimental tests of general relativity and of theoretical frameworks for analysing them are reviewed. Einstein’s equivalence prin-ciple (EEP) is well supported by experiments such as the Eötvös experi-ment, tests of special relativity, and the gravitational redshift experiment. Fut ..."

...tional Lagrangian here takes the form of a scalar-tensor theory (Sec. 3.3.2). But the non-metric electromagnetic term will, in general, produce violations of EEP. For examples of specific models, see =-=[125, 50]-=-. Thus, EEP and related tests are now viewed as ways to discover or place constraints on new physical interactions, or as a branch of “non-accelerator particle physics”, searching for the possible imp...

"... We review the general relativistic theory of the motion, and of the timing, of binary systems containing compact objects (neutron stars or black holes). Then we indicate the various ways one can use binary pulsar data to test the strong-field and/or radiative aspects of General Relativity, and of ge ..."

We review the general relativistic theory of the motion, and of the timing, of binary systems containing compact objects (neutron stars or black holes). Then we indicate the various ways one can use binary pulsar data to test the strong-field and/or radiative aspects of General Relativity, and of general classes of alternative theories of relativistic gravity.

"... The Laser Astrometric Test Of Relativity (LATOR) is a Michelson-Morley-type experiment designed to test the metric nature of gravitation – a fundamental postulate of Einstein’s general theory of relativity. The key element of LATOR is a geometric redundancy provided by the long-baseline optical inte ..."

The Laser Astrometric Test Of Relativity (LATOR) is a Michelson-Morley-type experiment designed to test the metric nature of gravitation – a fundamental postulate of Einstein’s general theory of relativity. The key element of LATOR is a geometric redundancy provided by the long-baseline optical interferometry and interplanetary laser ranging. By using a combination of independent time-series of gravitational deflection of light in the immediate proximity to the Sun, along with measurements of the Shapiro time delay on interplanetary scales (to a precision respectively better than 0.1 picoradians and 1 cm), LATOR will significantly improve our knowledge of relativistic gravity and cosmology. The primary mission objective is i) to measure the key post-Newtonian Eddington parameter γ with accuracy of a part in 10 9. 1 2 (1 − γ) is a direct measure for presence of a new interaction in gravitational theory, and, in its search, LATOR goes a factor 30,000 beyond the present best result, Cassini’s 2003 test. Other mission objectives include: ii) first measurement of gravity’s non-linear effects on light to ∼0.01 % accuracy; including both the traditional Eddington

"... This paper describes advances in microwave frequency standards using laser-cooled atoms at BNM-SYRTE. First, recent improvements of the 133 Cs and 87 Rb atomic fountains are described. Thanks to the routine use of a cryogenic sapphire oscillator as an ultra-stable local frequency reference, a founta ..."

This paper describes advances in microwave frequency standards using laser-cooled atoms at BNM-SYRTE. First, recent improvements of the 133 Cs and 87 Rb atomic fountains are described. Thanks to the routine use of a cryogenic sapphire oscillator as an ultra-stable local frequency reference, a fountain frequency instability of 1.6 × 10 −14 τ −1/2 where τ is the measurement time in seconds is measured. The second advance is a powerful method to control the frequency shift due to cold collisions. These two advances lead to a frequency stability of 2 × 10 −16 at 50 000 s for the first time for primary standards. In addition, these clocks realize the SI second with an accuracy of 7 × 10 −16, one order of magnitude below that of uncooled devices. In a second part, we describe tests of possible variations of fundamental constants using 87 Rb and 133 Cs fountains. Finally we give an update on the cold atom space clock PHARAO developed in collaboration with CNES. This clock is one of the main instruments of the ACES/ESA mission which is scheduled to fly on board the International Space Station in 2008, enabling a new generation of relativity tests. 1 1 Introduction: Einstein’s

...amental constants on different timescales, geological timescale [20, 21] and cosmological timescale [22, 23]. Nearly all unification theories (in particular string theories) violate EEP at some level =-=[24, 25, 26]-=- which strongly motivates experimental searches for such violations. Tests described here are based on highly accurate comparisons of atomic energies. In principle, it is possible to express any atomi...